Industrial floor scrubbers typically include a cleaning solution tank, a solution delivery system to apply the cleaning solution to the floor in front of one or more rotating cylindrical or disc scrub brushes for cleaning the floor, a squeegee located aft of the scrub brushes for drying the floor, a vacuum system for reclaiming the cleaning solution, and a recovery tank for holding the reclaimed cleaning solution. In addition, floor scrubbers that employ cylindrical scrub brushes are frequently provided with a debris hopper located aft of the scrub brushes to catch wet debris swept from the floor by the typically counter-rotated scrub brushes. One advantage of this system is that it prevents debris from getting caught in the rear squeegee which would degrade drying of the floor by the squeegee.
Floor scrubber utility has recently been enhanced so as to provide the scrubber with a dry sweep capability, as opposed to merely scrubbing the floor using a water solution. To that end, dry sweep systems have been developed for use in some floor scrubbers. These dry sweep systems typically incorporate rubber skirts, or baffles, disposed around the perimeter of the floor engaging scrub brushes for the purpose of containing dust produced during the dry sweep operation. These modified floor scrubbers also sometimes include a dust filter mounted to an upper portion of a debris hopper, and a second separate vacuum impeller system to vacuum the debris hopper and draw the dust-laden air through the dust filter, as well as an intermittently operated filter shaker for shaking the filter clean. This system is very similar in operation to a standard dedicated floor sweeper.
Field use has demonstrated that there is a basic problem with this type of dry sweep system. When operating this type of machine as a floor scrubber, a large amount of water is swept, along with any collected debris, into the debris hopper. Most of this liquid is suctioned away from the debris hopper using a small vacuum hose that taps into a main rear squeegee vacuum hose. The dry sweep dust filter, even though not used when scrubbing and not transmitting air during scrubbing operations, becomes saturated and clogged with moisture and wet debris primarily due to its close proximity to the debris hopper. As a result, the saturated dry filter becomes ineffective when needed as a dry dust filter. It is then necessary for the operator to remove, wash, dry and replace the dust filter, or to replace the dust filter with a new filter before attempting to dry sweep.
Due to the relatively small debris hopper volume and other considerations, scrubbers used as dry sweepers are not intended to be as effective as a dedicated floor sweeper. If the floor environment is considered to be severe, or “out of control”, due to the presence of large amounts of dust and/or debris, then the use of a dedicated floor sweeper is typically recommended to bring the environment under control before scrubbing or scrubber dry sweeping is attempted.